The dollar declined against other major currencies in European trading while the U.S. stock market rose just a hair, 9.45 points, in relatively moderate trading.

``Generally the response to the agreement was just lukewarm,`` said Steve Roach, economist for Morgan Stanley & Co., an investment banking firm.

``It was not a disaster, but it was not a solution. We are just muddling through.``

President Reagan and congressional leaders agreed Friday on a plan to reduce the budget deficit by $30 billion in fiscal 1988 and by $46 billion in fiscal 1989.

Reagan met with business and financial leaders at the White House and said that ``this agreement must not be the last word on deficit reduction. This is a good first step. We can and should do more.`` The President said, however, that ``I will veto a bad tax bill`` if one emerges from Congress.

When a reporter noted the markets seemed unimpressed with the budget deal, Reagan quipped: ``They probably haven`t looked at it yet.``

Allen Sinai, chief economist for Shearson Lehman Brothers, called reaction to the budget deal disappointing and said financial markets now will focus on news other than the budget.

``Any adverse economic news could prove difficult,`` Sinai said. Poor economic indicators or a breakdown in international cooperation on the dollar and interest rates ``could be the straw that breaks the camel`s back,`` he said.

Sinai said a ``smaller version`` of the Oct. 19 stock market crash, in which the Dow Jones Industrial Average fell by 508 points, is possible.

``The reaction is just so-so. It`s important that they reached an agreement because otherwise we would have had a disaster,`` said David Wyss, economist for Data Resources Inc. ``But they did the least they could have done.``

Financial markets found the budget deal lacking on several points. Analysts said it did not reduce the budget deficit enough and contained gimmicks, such as federal asset sales, that would fail to make a major dent in the real causes of the deficit.

They also said the budget deal might not pass Congress because of Republican opposition to tax increases. The measure would boost taxes by $9 billion in the first year and $14 billion in the second.

Market opinion was divided on whether the U.S. and its major trading partners should meet to reach a new agreement on the value of the dollar.

Roach said such a meeting now would be a mistake. ``There have been some lessons learned in the markets,`` he said. ``One of them is that currency stability should take a back seat to managing the domestic economy.``

Nevertheless, the administration is preparing for a new meeting of the Group of Seven, the finance ministers of the top seven industrial countries, sometime in the next several weeks to consider, among other things, a plan to stabilize the dollar.

Treasury Secretary James Baker said Friday that he wanted to make sure the budget package is carried out by Congress before he agrees to a Group of Seven meeting. He also wants ironclad assurances that West Germany and Japan will agree to cut interest rates or taxes as part of any new dollar deal.

One official said the U.S. wants the freedom to back out of a dollar deal if it appears the nation is headed for recession.

The last dollar agreement, reached at the Louvre in Paris in February, generally is considered a major mistake because it set the value of the dollar too high. Many critics believe that dollar-support operations made necessary by the Louvre accord forced the U.S. to raise interest rates, contributing to the stock market crash.

The dollar dropped against all major currencies in European trading, to 1.6689 West German marks, down from 1.6820 marks on Friday, and to 134.7 Japanese yen, down from 135.55 on Friday.

Economist Wyss said he expected the dollar to continue to weaken.

Rudy Penner, former director of the Congressional Budget Office, called the situation in the financial markets ``scary,`` because private foreign investors are growing less willing to put their funds in the U.S.

Alan Stoga, economist for Kissinger & Associates, said foreign central banks, not private foreign investors, are now the most active lenders to the U.S. This means the governments of Japan and Europe are directly financing a large part of the U.S. budget deficit.

``The issue for 1988 is how the United States is going to finance itself without raising interest rates,`` he said.

The financial situation was a major topic of the meeting at the White House between Reagan and the heads of several major corporations.

John Phelan, president of the New York Stock Exchange, called the budget agreement a beginning and called it much better than across-the-board cuts under the Gramm-Rudman balanced-budget law.